WO2009040808A1

WO2009040808A1 - Abdominal muscle exercise apparatus and method

Info

Publication number: WO2009040808A1
Application number: PCT/IL2008/001283
Authority: WO
Inventors: Ilan Mandil
Original assignee: Ilan Mandil
Priority date: 2007-09-25
Filing date: 2008-09-24
Publication date: 2009-04-02
Also published as: IL186281A0

Abstract

An abdominal muscle exercise apparatus and method are disclosed with use of an element (15) that is angularly displaceable about a horizontal axis from a starting angle to an ending angle with respect to an underlying horizontal surface. Displacement of the element is initiated upon application of a bodily initiated force thereto during execution of an abdominal exercise. An instantaneous angle (A) of a selected portion of the element with respect to the horizontal surface is determined, to indicate an exerciser performance that is achieved during abdominal exercises. In one embodiment, a core muscle strengthening exercise system and method include supporting a first bodily portion in unstabilized fashion, supporting a second bodily portion in stabilized fashion, and performing a desired exercise, whereby core muscles are forced to tense in response to a selected orientation of the first bodily portion in order to ensure body stability during the course of the exercise.

Description

ABDOMINAL MUSCLE EXERCISE APPARATUS AND METHOD

Field of the Invention

The present invention relates to the field of sport equipment. More particularly, the invention relates to an apparatus for strengthening the abdominal muscles.

Background of the Invention

Many exercise machines for strengthening the abdominal muscles are known in the prior art, including US 5,098,089, WO 2007/009244, US 2004/0097837, and JP 10230022. The resistance that the abdominal muscles encounter is mainly dependent upon the inclination of the surface on which the exerciser rests.

Even though many of the prior art abdominal exercise machines can monitor the inclination angle of the support surface and the number of repetitions performed by the exerciser, they are not capable of evaluating the performance of the exerciser. That is, the strengthening of abdominal muscles is influenced by not just the inclination angle of the support surface corresponding to the starting angle of the exerciser during an abdominal exercise, assuming that the back of the exerciser is parallel therewith, but also with the ending angle of the exerciser.

It is an object of the present invention to provide an abdominal muscle exercise apparatus and method by which the starting and ending angles of the back of an exerciser can be determined.

It is an additional object of the present invention to provide a monitoring system using the abdominal muscle exercise apparatus to determine the performance of the exerciser.

It is an additional object of the present invention to provide a monitoring system using the abdominal muscle exercise apparatus to provide an alert to an exerciser when poor exercise performance is detected. Other objects and advantages of the invention will become apparent as the description proceeds.

Summary of the Invention

The present invention provides a method for selectively conditioning abdominal muscles, comprising the steps of providing an element that is angularly displaceable about a horizontal axis, selecting a starting angle and an ending angle of said element with respect to an underlying horizontal surface, and applying a bodily initiated force onto said element during execution of an abdominal exercise, whereby to angularly displace said element . and to condition selected abdominal muscles or portions of abdominal muscles.

In prior art abdominal exercise methods, abdominal muscles are tensed only during approximately 30 percent of the movement of an exerciser from a first to second angular position with respect to an underlying horizontal surface. The remaining angular movement is effected as a result of the tension of leg muscles, particularly the quadriceps muscles. Heretofore, those that suffer from certain leg injuries or are crippled have been unable to perform abdominal exercises without injuring other bodily portions.

According to the method of the present invention, abdominal exercises are performed with less involvement of the leg muscles with respect to prior art methods so that a much greater number of people can perform abdominal exercises. An exerciser, whether a beginner or an experienced sport practitioner, can effectively condition the abdominal and lower back muscles by being able to select the starting and ending angles of the angularly displaceable element to which a bodily initiated force is applied during the course of the exercise and thereby selecting a level of difficulty. Moreover, those have limited abdominal and lower back mobility, such as those that suffer from strained or torn abdominal or lower back muscles, or women following childbirth, can select the starting and ending angles of the element to selectively heal, rehabilitate, treat or strengthen (hereinafter "condition") weak, injured or painful abdominal or lower back muscles.

In one aspect, a device for resisting the bodily initiated force applied to the element is provided and a resisting force applied by the device is adjusted, to further assist in conditioning weak, injured or painful abdominal or lower back muscles. The terms "resisting device" and "resisting mechanism" may be used interchangeably.

When the exerciser sits on a leg support facing a back support and the resisting device is employed, abdominal muscles are tensed while the element is angularly displaced both rearwardly and forwardly following application of a force by the abdomen or by the chest onto the element.

When the exerciser sits on the leg support facing away from the back support, the element is angularly displaced following application of a force by the back onto the element. Abdominal muscles are accordingly tensed when the element is forwardly displaced from its ending angle to its starting angle while the exerciser changes his or her corresponding disposition.

In one aspect, an instantaneous angle of a selected portion of the element with respect to the horizontal surface is determined, said instantaneous angle being indicative of an exerciser performance that is achieved during abdominal exercises.

The present invention is also directed to an abdominal muscle exercise apparatus, comprising: a. a leg support; b. an element that is angularly displaceable about a horizontal axis from a starting angle to an ending angle with respect to an underlying horizontal surface, said horizontal axis coinciding with an axle mounted in, or vertically spaced from, said leg support, , wherein displacement of said element is initiated upon application of a force by a bodily portion of an exerciser thereto during execution of an abdominal exercise; and c. means for determining an instantaneous angle of a selected portion of said element with respect to said horizontal surface, said instantaneous angle being indicative of an exerciser performance that is achieved during abdominal exercises.

The instantaneous angle determining means is preferably a location detector for detecting an instantaneous location of an element characteristic region and means for correlating said instantaneous location to an instantaneous angle of the selected element portion with respect to the horizontal surface. By determining an instantaneous location of a characteristic region of the element and knowing the configuration of the element, the instantaneous angle of the selected portion of the element will also be determined.

In one aspect, the correlating means is a measurement unit in which the location detector is housed

In one aspect, the location detector is an optical detector or a potentiometer.

The measurement unit preferably comprises a controller which receives a signal generated by the location detector, said signal being indicative of the instantaneous location of the characteristic region of the element. The controller is adapted to extract relevant parameters associated with the abdominal exercise from the received signal and to store the parameters in a log.

Various exercise related parameters that are stored include starting angle of exercise, ending angle, difference between starting and ending angles, duration of arm displacement between the starting and ending angles, leg orientation, the number of exercises performed, the interval between exercises, and the number of sets of exercises performed. If more than one exerciser uses the apparatus, a user name may be input by means of a selector in communication with the controller, and the relevant data stored in the log will then be associated with the specified user. Stored or selected exercise related parameters can be viewed on a display or retrieved by a data interface.

The controller is operable in a controlled exercise mode, during which exercise related parameters are controlled with respect to past performance or with respect to a user selected performance level, or in an uncontrolled exercise mode, during which exercises are performed without comparison to controlled parameters.

A user exercising in a controlled exercise mode is alerted when one or more parameters of a currently performed exercise have a level inferior to that of the controlled parameters, such as by means an enunciator that emits an audible sound. An exerciser or a trainer thereof can therefore guide an exercise program with respect to stored or selected exercise related parameters.

In one aspect, the instantaneous angle determining means is a visual indicator.

In one embodiment, the element is a back support that is pivotally connected to the leg support.

In one aspect, the back support is connected to one or more rails upwardly extending from a swingable plate, said swingable plate being pivotally connected to a first axle mounted to an underside portion of the leg support.

The apparatus can be compactly stored when not in use such that the rails are folded or pivoted onto the swingable plate.

In one aspect, the apparatus further comprises an enclosure for each rail and a slide element substantially parallel to the one or more rails which is slidingly engageable with a corresponding rail enclosure, said slide element being displaceable with respect to a corresponding rail following upon application of a force by the bodily portion of an exerciser onto the back support.

Front and rear stops are preferably pivotally connected to second and third axles, respectively, mounted to corresponding underside portions of the leg support, said front and rear stops adapted to delimit the angular displacement of the swingable plate.

In one aspect, the apparatus further comprises a mechanism for adjustably resisting a force applied to the back support.

In one embodiment, the element is a circumferentially displaceable arcuate arm which is biased to normally protrude from a back support and is retractable when the bodily portion of exerciser applies a force thereto.

An arcuate, continuous guide way having substantially the same curvature as that of the arm is formed in both a measurement unit body and in an overlying back support body. The arm is insertable within the guide way and is urged thereby to follow a circumferential path therealong, passing through a recess formed in the back support. The arm is upwardly biased by means of a spring or a torsion rod.

In one aspect, the location detector comprises at least one elongated microswitch protruding from a surface of the arm and a plurality of flexible, electrically conductive levers protruding from the measurement unit body into a guide way interior, a microswitch being configured to cause a lever to pivot when being contacted thereby when the characteristic region of the element is in the vicinity of the corresponding lever.

In one aspect, the back support is height adjustable. In one aspect, the apparatus further comprises means for retaining the back support at a desired angular orientation with respect to the underlying horizontal surface.

In one aspect, the back support retaining means is a telescoping post. The apparatus can be compactly stored when not in use such that the post is folded to the underside of the back support and the back support is folded onto the top of the leg support.

In one aspect, the apparatus further comprises means for maintaining legs in a raised position.

The present invention is also directed to a core muscle strengthening exercise method, comprising the steps of supporting a first bodily portion in unstabilized fashion, supporting a second bodily portion in stabilized fashion, and performing a desired exercise, whereby core muscles are forced to tense in response to a selected orientation of said first bodily portion in order to ensure body stability of an exerciser during the course of said exercise.

As referred to herein, a bodily portion is supported in "stabilized fashion" when all reactive force components are equal and opposite to corresponding force components applied by said bodily portion. A bodily portion is supported in "unstabilized fashion" when said bodily portion engages an element that applies one or more reactive force components such that said one or more reactive force components are not equal and opposite to corresponding force components applied by said bodily portion. The core muscles are therefore forced to tense to ensure body stability when said bodily portion engages said element, whether applying a static or dynamic force to said element.

In many prior art core muscle exercise methods, a bodily portion remains unsupported for extended periods of time, causing the core muscles to be tensed for a similar period of time. Since the level of difficulty of prior art exercise methods for strengthening the core muscles is generally high, only experienced sport practitioners can perform certain exercises, particularly when a number of repetitions are recommended.

In contrast, the method of the present invention whereby a first bodily portion which is preferably a bodily extremity is supported in unstabilized fashion and a second bodily portion is supported in stabilized fashion, allows beginners and other inexperienced exercisers to exercise the core muscles for extended periods of time or by a selected number of repetitions.

Preferably, a third bodily portion is also supported in stabilized fashion.

The first bodily portion may be a foot or a hand.

The exercise that is performed may be selected from the group of curls, barbell curls, reverse curls, one-arm seated dumbbell triceps extensions, seated dumbbell presses, front dumbbell presses, alternate front arm raises, one-dumbbell front raises, bench presses, dumbbell flies, inclined dumbbell presses, dumbbell pullovers, right rows, dumbbell shrugs, sit-ups, gym ladder sit-ups, retaining the first bodily portion in an outstretched position for an extended period of time, and an exercise in conjunction with a training belt.

The present invention is also directed to a system for strengthening core muscles, comprising means for supporting a first bodily portion in unstabilized fashion, and a first surface for supporting a second bodily portion in stabilized fashion, whereby core muscles are forced to tense in response to a selected orientation of said first bodily portion in order to ensure body stability of an exerciser during the course of an exercise.

In one aspect, the system further comprises a second surface for supporting a third bodily portion in stabilized fashion, said second surface being angularly spaced from the first surface. In one aspect, the means for supporting a first bodily portion in unstabilized fashion is height adjustable.

In one aspect, the means for supporting a first bodily portion in unstabilized fashion is a freely rotatable ball element to which is connected at least one element engageable by the first bodily portion.

In one aspect, the ball element is rotatably mounted within a bearing element which is attached to a bearing holder, said bearing holder being releasably securable to a post at a desired height.

In one aspect, the post is connected to a stool unit spaced from the first surface.

In one aspect, the means for supporting a first bodily portion in unstabilized fashion is a cable downwardly extending from a ceiling portion to which is connected at least one element engageable by the first bodily portion.

The present invention is also directed to a Pilates exercise method, comprising the steps of providing an element that is angularly displaceable about a horizontal axis, selecting a starting angle and an ending angle with respect to an underlying horizontal surface of said element, providing a device for resisting a bodily initiated force applied to said element, adjusting a resisting force applied by said device, and applying a bodily initiated force to said element, whereby to angularly displace said element and to strengthen selected muscles.

The magnitude of the resisting force is preferably substantially constant, to prevent potential injuries resulting from an excessively quick-reacting element that angularly displaces upon release of the bodily initiated force.

In one aspect, the bodily initiated force is applied by a hand, foot or back. In one aspect, the bodily initiated force is applied when an exerciser is in a sitting, standing or reclining position.

Brief Description of the Drawings

In the drawings:

- Fig. 1 is a schematic side view of an abdominal muscle exercise apparatus, according to one embodiment of the present invention;

- Fig. 2 is a schematic side view of a circumferentially displaceable arm, for determining the starting and ending angles of the back of an exerciser during the course of an abdominal exercise;

- Fig. 3 is a schematic, vertical cross sectional view of a back support and an underlying measurement unit, showing a guide way through which an arm is displaced and means for biasing the arm;

- Figs. 4 and 5 are a schematic, vertical cross sectional view of two location detectors, respectively, for determining the instantaneous location of a circumferentially displaceable arm;

- Fig. 6 is a block diagram of a controller which processes signals received from a location detector;

- Fig. 7 is a schematic illustration of a system for monitoring the performance of a plurality of users who are undergoing an abdominal muscle exercise program;

- Fig. 8 is a perspective view of another embodiment of an abdominal muscle exercise apparatus;

- Fig. 9 is a schematic, vertical cross sectional view of a back support and an underlying measurement unit, showing another embodiment of means for biasing the arm;

- Fig. 10 is a perspective view of another embodiment of the exercise apparatus;

- Fig. 11 is a perspective view of yet another embodiment of the exercise apparatus;

- Fig. 12 is a perspective view of yet another embodiment of the exercise apparatus wherein the back support is angularly displaceable; - Fig. 13 is a side view of the apparatus of Fig. 12, showing the back rest in a plurality of angular positions;

- Fig. 14 is a schematic, perspective view of portions of the back support and leg support of Fig. 12, showing an interface therebetween and a sensor by which exercise related parameters are extracted;

- Fig. 15 is a side view of yet another embodiment of an exercise apparatus having an angularly displaceable back support;

- Fig. 16 is a perspective view from the rear of the apparatus of Fig. 15;

- Fig. 17 is an enlargement of Fig. 16;

- Fig. 18 is a perspective view from the side of a portion of the apparatus of Fig. 15 adjoining the interface between the back support and leg support;

- Fig. 19A is a perspective view from the side of the leg support of Fig. 15, showing a device for resisting a bodily initiated force applied to the back support;

- Fig. 19B illustrates an exerciser performing abdominal exercises with the use of the apparatus of Fig. 15 while sitting in an upright position and facing the back support;

- Fig. 20 is a perspective view of an exercise apparatus according to yet another embodiment of the invention by which core muscles are strengthened when a bodily portion is supported in unstabilized fashion with respect to a freely dangling cable;

- Fig. 21 is a side view of an exercise apparatus according to yet another embodiment of the invention by which core muscles are strengthened when a bodily portion is supported in unstabilized fashion with respect to a freely rotatable ball element;

- Fig. 22 is a side view of the ball element of Fig. 21, showing leg rest attached thereto and a bearing element in which it is mounted;

- Fig. 23 is a vertical cross sectional view of the apparatus of Fig. 21, showing a bearing holder as it is secured to a post while the ball element is removed from the bearing;

- Fig. 24 is a side view of an exercise apparatus according to yet another embodiment of the invention comprising a repositionable stool unit, to which is releasably connected a post for supporting the ball element of Fig. 21 and which is placed in front of a leg support; - Fig. 25 is a side view of the apparatus of Fig. 24 as the stool unit is placed in abutting relation with a front portion of the leg support;

- Fig. 26 is a side view of the apparatus of Fig. 24 as the stool unit is connected to the top of the leg support; and

- Fig. 27 is a perspective view of yet another embodiment of the exercise apparatus, showing a damper for providing a substantially constant resisting force to the angularly displaceable back support.

Detailed Description of Preferred Embodiments

Fig. 1 illustrates the novel abdominal muscle exercise apparatus of the present invention, which is indicated generally by numeral 10, according to one embodiment of the invention. Exercise apparatus 10 comprises planar leg support 3 covered by mat 5 for comfortably supporting the legs of exerciser 2, planar back support 7 which is pivotally connected to mat 5 by means of axle 9, telescoping post 12, which contacts back support 7 and is preferably vertically disposed as shown, and circumferentially displaceable arm 15, which is normally biased to protrude from back support 7, yet is retracted into back support 7 when the back of exerciser 2 applies a force thereto, such as when contacting back support 7. When not in use, apparatus 10 can be compactly stored, with post 12 being folded to the underside of back support 7, and back support 7 being folded onto the top of mat 5.

The height of post 12 is selected so as to set back support 7 at a predetermined inclination angle I with respect to mat 5. Post 12 is suitable for bearing the weight of exerciser 2, and inclination angle I may be set thereby from 60-180 degrees, depending on a difficulty level selected by the exerciser or a trainer thereof. During an abdominal exercise, back 13 of exerciser 2 moves along a circumferential path, e.g. such as when the starting angle of back 13 coincides with inclination angle I, as indicated by arrow 19. As back 13 moves away from back support 7, such as to position B or B', less force is applied on arm 15. Arm 15 is therefore correspondingly circumferentially displaced, following the movement of back 13. Arm 15 is configured to be displaced a circumferential angle A ranging from 45-180 degrees with respect to mat 5.

It will be appreciated that apparatus 10 may be provided with any other suitable means for retaining back support 7 at a desired angular orientation with respect to an underlying horizontal surface.

Referring now to Fig. 2, arm 15 has an arcuate bar 14 configured with a radius of curvature R, e.g. having a circular or square cross section, and a terminal planar engagement surface 16 attached to, or solid with, upper end 17 of bar 14, for contacting the back of the exerciser. The width of engagement surface 16 is greater than that of bar 14. Measurement unit 25, which is attached to the underside of back support 7 and comprises a transducer and controller, measures the instantaneous location of lower end 23 of bar 14, or any other characteristic region of bar 14, as it is circumferentially displaced, and converts the measured location to an electrical signal. By being able to measure the instantaneous location of the lower end of bar 14, the instantaneous angle A of engagement surface 16 will therefore be determined. Since engagement surface 16 contacts the back of the exerciser, the starting and ending angles of back 13 during the course of an abdominal exercise may therefore also be advantageously determined. Also, the starting angle need not coincide with inclination angle I. Data related to each abdominal exercise performed by the exerciser, including starting angle, ending angle, number of exercises, and interval between exercises is stored and processed, to determine the performance of the exerciser during the abdominal exercises. The performance of the exerciser is determined by predetermined criteria, and can be compared with the performance that was determined at a different day or hour.

As arm 15 is displaced along circumferential path 19 during the course of an abdominal exercise, the instantaneous angle of engagement surface 16 changes from A to A'. When the exerciser is fully reclined, the back contacts back support 7 and engagement surface 16 is received within recess 11 of similar configuration. Fig. 3 illustrates one embodiment of a measurement unit 25A. Measurement unit 25A has a solid body 31, e.g. rectilinear as shown, in which is formed an arcuate guide way 34 having the same curvature as that of bar 14 of the arm. Continuous guide way 34 is formed in both measurement unit body 31 and in the body of back support 7, which overlies measurement unit 25A. A spring 37 is mounted to a bottom portion of guide way 34 and is upwardly biased, as indicated by arrow 38. Bar 14 is insertable within guide way 34 and is urged thereby to follow a circumferential path along guide way 34, passing through recess 11 formed in back support 7. After the arm is inserted within guide way 34, lower end 23 contacts spring 37 and is therefore also upwardly biased. When the back of the exerciser contacts the engagement surface of the arm, spring 37 is compressed, and the arm is downwardly displaced.

Measurement unit 25A also comprises one or more location detectors 42, for detecting the relative location of lower end 23 of bar 14, and a controller 44 which receives a signal S from location detector 42 which is indicative of the relative location of lower end 23. Signal S is typically conducted through a wire, but it may also be transmitted to controller 44 by wireless means.

In Fig. 4, the location detector comprises a plurality of light emitters, e.g. emitters 45a and 46a, and a plurality of light detectors, e.g. detectors 45b and 46b, positioned to receive the light emitted from a corresponding emitter. The emitters and detectors are embedded in, or otherwise attached to, body 31 of the measurement unit so as to be facing the interior of guide way 34. As shown, bar 14 is interposed between emitter 45a and detector 45b, causing light beam 49a generated by emitter 45a to be reflected by the bar and not to be received by detector 45b. However, bar 14 has not yet been sufficiently displaced downwardly to reflect light beam 51 emitted by emitter 46a. When light beam 51 impinges detector 46b, the latter generates a signal which is indicative that the bottom end of bar 14 is above detector 46b. By providing a plurality of pairs of emitters and detectors, the instantaneous location of bottom end 23 may be more accurately determined. It will be appreciated that any other type of optical detector well known to those skilled in the art may be used to detect the location of bottom end 23.

In Fig. 5, the location detector comprises at least one microswitch protruding from the surface of bar 14 and a plurality of flexible levers protruding from body 31 of the measurement unit into the interior of guide way 34, e.g. microswitch 62 and flexible lever 63. The microswitch is elongated and configured to cause a lever to pivot when being contacted thereby as bar 14 is displaced to a region in the vicinity of the corresponding lever. As both the microswitch and are lever are electrically conductive, an electrical signal is generated when the microswitch passes over, and contacts, a lever. Thus the instantaneous location of the lower end of bar 14 may be determined by sequentially receiving a signal from different levers as bar 14 is circumferentially displaced.

Fig. 6 illustrates a block diagram of controller 44. Controller 44 has a signal input 67 from the location detector, whether being a wired or wireless input. A location signal received by controller 44 is processed by processor 69, and the relevant parameters associated with the abdominal exercise are extracted and stored in log 71. Timer 73 determines the interval between the performance of two exercises, and this data is also stored in log 71. Various exercise related parameters that are stored include starting angle of exercise, ending angle, difference between starting and ending angles, duration of arm displacement between the starting and ending angles, the number of exercises performed, the interval between exercises, and the number of sets of exercises performed. If more than one exerciser uses the apparatus, a user name may be input by selector 75 and the relevant data stored in log 71 will then be associated with the specified user.

Following input of the user name, the user is requested to specify whether he or she is interested in performing a controlled exercise. As referred to herein, a "controlled exercise" means an exercise, or set of exercises, for which the parameters thereof are controlled with respect to past performance or with respect to a user selected performance level. That is, a user exercising in a controlled exercise mode is alerted when one or more parameters of a currently performed exercise have a level inferior to that of the controlled parameters. An "inferior level" is one that is indicative that the resistance to the abdominal muscles of the exerciser is less than the controlled level. For example, an inferior level is detected when the controlled starting angle is 120 degrees while the currently performed starting angle is 110 degrees. Alternatively, an inferior level is detected when the controlled ending angle is 70 degrees while the currently performed starting angle is 60 degrees. In an "uncontrolled exercise", an exerciser may choose to exercise in any desired fashion without comparison to controlled parameters. The exercise related parameters are stored in log 71 even though the user is exercising in the uncontrolled mode.

During the course of an exercise program, particularly when exercising in the controlled mode, the exerciser may receive feedback as to the instantaneous performance, e.g. by means of enunciator 77. When, for example, the exerciser raises his back to a selected starting angle, enunciator 77 may emit an audible sound, such as a beep or a recorded message, if the deviation between the selected starting angle and the controlled starting angle is greater than a predetermined value. Similarly, enunciator 77 will emit an audible sound for a deviation from any other exercise related parameter, such as exercise repetition rate. The exerciser or a trainer thereof can therefore a guide an exercise program with respect to stored or selected exercise related parameters. Stored or selected exercise related parameters can be viewed on display 78 or retrieved by data interface 79, e.g. by means of a removable memory card.

Fig. 7 illustrates a system 85 for monitoring the performance of a plurality of users who are undergoing an abdominal muscle exercise program. As each user performs abdominal exercises by means of a corresponding apparatus, e.g. apparatus 10D-F as shown, measurement units 25D-F generate signals SD-F, respectively, which are indicative of the relative location of the lower end of the corresponding circumferentially displaceable arm. Signals SD-F are transmitted via data network 86, e.g. the Internet, to server 81, which stores each signal and associates the same with the corresponding user. Server 81 processes the stored data and determines a user performance. A performance alert signal, e.g. signal PE, will be generated and transmitted to the corresponding measurement unit, when one or more parameters of a currently performed exercise have a level inferior to that of the controlled parameters.

In addition to storing user specific data, server 81 may also store a plurality of sets of exercise related parameters wherein each set is representative of a different performance level. A user exercising in the controlled mode may select a training program consisting of a predetermined sequence of sets of exercise related parameters. Following user selection, server 81 transmits a performance level signal L, e.g. signal LD, which is representative of a specific set of parameters, to the data interface of the corresponding measurement unit. The instantaneous performance of the exerciser can then be compared with the controlled performance. The next highest performance level may be selected by the user, such as when he feels that his performance has improved, or may be automatically transmitted at fixed time intervals, e.g. once a week. If so desired, the user can substitute server transmitted set of parameters with a user selected set of parameters.

In Fig. 8, apparatus 90 comprises arm 95 formed with a toothed inner surface 96, which is in engagement with a gear (not shown), for guiding arm 95 along a circumferential path, or alternatively, kinematically connected with the location detector. Arm 95 is upwardly biased by means of appendage 97 extending from arm 95, so that engagement surface 16 of arm 95 normally protrudes from back support 7. Spring 99 in turn connects appendage 97 to back support 7.

Fig. 9 illustrates an embodiment of the invention in which arm 15 is upwardly biased by means of a prestressed torsion rod 105. Torsion rod 105 is anchored at one end thereof to support means 107, which may be connected to housing 108 of measurement unit 25B, underside 114 of back support 7, or to any selected stationary element such as a bearing ring mounted on the axle connecting the leg support and back support, and is attached at a second, unsupported end thereof to lower end 23 of arm 15. When the back of an exerciser applies a force to arm 15, the latter is downwardly displaced and torsion rod 105 is twisted downwardly, in the rotational direction as indicated by arrow 112. When the force applied to arm 15 is released, torsion rod 105 assumes a relaxed state and is twisted upwardly as a result of being prestressed, in the rotational direction as indicated by arrow 111. Arm 15 connected to torsion rod 105 is therefore upwardly displaced through guide way 34.

Fig. 10 illustrates another embodiment of the invention in which apparatus 120 is provided with a plurality of anchoring hooks 125, through one or more of which can be inserted a training belt, e.g. made of rubber. Anchoring hooks 125 protrude from the periphery of leg support 3 or from back support 7, at any selected spacing between adjacent anchoring hooks. The selection of through which anchoring hooks a training belt is fed influences which muscle groups can be strengthened. For example, a training belt fed through anchoring hooks 125a and 125b protruding from opposite sides of back support 7 and held at its two ends by the two hands of the user, respectively, will strengthen the triceps when tensioned.

Each anchoring hook 125 is preferably arcuate, e.g. semicircular, and parallel to the corresponding support surface, although other shapes and orientations are also suitable. To facilitate storage, the anchoring hooks may be retractable within the body of the support surface by any method well known to those skilled in the art. Prior to feeding a training belt into selected anchoring hooks, the selected anchoring hooks are extended from the body of the support surface such that they are fixed in position and can bear the load associated with a desired exercise.

Figs. 12-14 illustrate another embodiment of the invention wherein the back support is pivotally connected to the leg support. As shown in Fig. 12, exercise apparatus 150 comprises an arcuate leg support 153 and a back support 157 that is pivotally connected to leg support 153. Back support 157 is provided with two lateral extensions 159 which may be triangularly shaped, a head cushion 161 and a back cushion 163.

Fig. 13 illustrates three exemplary angular positions A, B, and C to which back support 157 is displaced as a result of a corresponding force applied thereto by the back of an exerciser.

Fig. 14 schematically illustrates how back support 157 is pivotally connected to leg support 153 and how the instantaneous angle of back support 157 with respect to an underlying horizontal surface is determined. Horizontally oriented shaft 161, which is carried by back support 157, is rotatably mounted within stationary shaft 162 connected to leg support 153. Location sensor 164, which may be a potentiometer or an encoder, interfaces between shafts 161 and 162 and senses the instantaneous angular position of shaft 161 relative to shaft 162. As a result of a known correlation of the instantaneous angular position of shaft 161 and the instantaneous angle of back support 157 with respect to the underlying horizontal surface, the performance of the exerciser during abdominal exercises may be determined. Data acquired by location sensor 164 may be transmitted to a controller, e.g. one housed in a measuring unit connected to the underside of leg support 153, which is adapted to extract exercise related parameters.

Figs. 15-19 illustrate another embodiment of an angularly displaceable back support to which is applied adjustable resistance.

Fig. 15 illustrates a side view of exercise apparatus 170. Exercise apparatus 170 comprises back support 177 which is pivotally connected to stationary, arcuate leg. support 173, head support 175 which is pivotally attached to the top of back support 177 and angularly separable from the latter by means of actuator 176, angularly displaceable front stop 178 and rear stop 179 for selecting the starting and ending angles of an abdominal exercise, and at least one gas spring 180 for applying an adjustable resistance to back support 177.

As shown in Fig. 16, leg support 173 is a curved plate which is formed with central openings 182 and 184 to accommodate the rearward and forward angular displacement, respectively, of back support 177. A seat 186 on which the exerciser sits is attached to leg support 177 between openings 182 and 184.

A rear view of back support 177 is shown in Figs. 16 and 17. Rails 191 and 192 upwardly extending at a fixed angle from swingable plate 195, e.g. 135 degrees, by means of attachments 198 and 199 are adapted to support back support 177. Each attachment comprises an abutment element 202 parallel and fixedly attached to the top face of swingable plate 195. A guard element 205 is substantially perpendicular to abutment element 202, and terminates at the seat end thereof with an elongated, upwardly extending element 209 defining the fixed angle at which rails 191 and 192 upwardly extend from swingable plate 195 and having a width substantially equal to the width of a rail. An axle 214 extends through the bottom of rails 191 and 192 and is seated within an aperture bored within corresponding elongated element 209. Back support 177 can be compactly stored on top of leg support 173 by rotating rails 191, 192 and back support 177 connected thereto about axle 214. When back support 177 is in an operational position, such as that shown in Fig. 17, a peg 211 located above axle 214 and associated with a pin mechanism, or any other suitable fixation device, is engaged with suitable means operatively connected to the elongated elements 209 which prevent the pivoting of rails 191, 192 relative to axle 214. When release member 178, which is located at the top end of rails 191, 192 and communicates with the pin mechanism, e.g. by cables, is actuated, the pin mechanism becomes disengaged with elongated elements and rails 191, 192 are free to pivot. Back support 177 can similarly be stored by other methods well known to those skilled in the art, e.g. by means of foldable struts 319 (Fig. 27) connected to one of the rails 191, 192 and to swingable plate 195, 199/31 129/08 and by the use of any suitable release member. Two L-shaped brackets 189 are connected to the rear face of back support 177, and leg 193 of each of which is connected to a corresponding slide element 201 so that back support 177 is substantially parallel to rails 191 and 192. A slide element 201 is slidingly engageable, e.g. by means of ball bearings, with a corresponding rail enclosure 203. The vertical spacing between back support 177 and seat 186 can be adjusted, e.g. by a distance of approximately 20 cm, by rearwardly displacing one or two substantially horizontally oriented handles 206 and 207 to thereby release one or more pins 208 of locking device 204 that is engageable with peg 211 and then applying an upward or downward force to handles 206, 207 so that slide elements 201 and rail enclosures 203 will be vertically displaced in a similar direction with respect to the rails. After handles 206 and 207 are vertically displaced to a desired height, they are forwardly displaced in order to reengage pins 208 with peg 211. Other configurations of the locking device may also be employed.

Slide elements 201 are employed in order to maximize the magnitude of the force applied by the exerciser's back onto rails 191 and 192. Since the axis of rotation of the exerciser's back is not coincident with the axis of rotation of swingable plate 195, slide elements 201 are displaced with respect to rails 191 and 192 following the application of a force by the exerciser's back onto back support 177, to compensate for the spacing between these two axes of rotation. Handles 206 and 207 limit the downward displacement of corresponding slide elements 201 and of back support 177 connected thereto.

Front stop 178 and rear stop 179 are shown in greater detail in Fig. 18. Front stop 178 is U-shaped, and its two legs are attached to a first axle rotatably mounted to the underside of leg support 173. Rear stop 179 also has an openwork configuration, and its two legs are attached to a second axle rotatably mounted to the underside of leg support 173. Knobs 212 and 215 are connected, e.g. kinematically connected by a reduction gear system, to the first and second axles, respectively, and are adapted to adjust the angular disposition of front stop 178 and rear stop 179, respectively, with respect to an underlying horizontal surface. If so desired, each of front stop 178 and rear stop 179 may be angularly displaced by means of an electrically, pneumatically or hydraulically actuated motor. A controller may govern the operation of the motor.

A third axle carried by the underside of swingable plate 195 is mounted between bearings 218 and 219, which are mounted to the underside of leg support 173. A location sensor interfaces with the third axle, and is used to determine the instantaneous angular position of back support 177 with respect to the underlying horizontal surface, such as by means of a controller 44 illustrated in Fig. 6.

Swingable plate 195 is mounted such that it is swingable between stops 178 and 179. The length of swingable plate 195 is greater than that of stops 178 and 179, so that when a lowermost portion thereof abuts a stop, the displacement of back support 177 in a similar direction is limited. Alternatively, the length of swingable plate 195 may be less than that of a stop when an attachment 222 is affixed to a lowermost region of the stop. In the example of Fig. 18, back support 177 is shown in an upright position at which additional forward angular displacement thereof is prevented by means of the contact between swingable plate 195 and rear stop 179. When the exerciser applies a force to back support 177, the latter is rearwardly displaced until swingable plate 195 contacts front stop 178.

The resistance mechanism to back support 177 is illustrated in Figs. 18 and 19A. The resistance to the motion of back support 177 is provided by gas springs 180 and 181, the structure and operation of which are well known to those skilled in the art and need not be described, for brevity. Front lead screw nut 226 and rear lead screw nut 228 are interposed between gas springs 180 and 181 such that each cylinder 231 is pivotally connected to front lead screw nut 226 and each piston rod 232 is connected to rear lead screw nut 228. Front lead screw 236 and rear lead screw 238 are engaged with nuts 226 and 228, respectively. Rear lead screw 238 is rotatably mounted within top and bottom bearings 235, which are mounted to the front face of swingable plate 195. Front lead screw 236 is rotatably mounted within top and bottom bearings 239, which are mounted to the rear face of stationary plate 241, the latter being attached to a wall bordering opening 184 formed within leg support 173. When front lead screw 236 is rotated by means of force adjustment knob 244, nut 226 is urged to be displaced therealong, causing a change in the length of piston rod 232 and in the resistance force applied to swingable plate 195. Similarly, rear lead screw 238 can be rotated by a corresponding force adjustment knob. Knob 244 may simultaneously rotate both front lead screw 236 and rear lead screw 238 when a pulley system 242, 243, or any other suitable transmission, connects the two lead screws. When back support 177 is rearwardly displaced, swingable plate 195 contacts rear lead screw nut 228 and forces piston rods 232 to be compressed until swingable plate 195 abuts front stop 178. If so desired, the force applied by gas springs 180 and 181 may be adjusted by means of a controller.

With use of the resistance mechanism, e.g. gas spring 180, as shown in Fig. 19B, abdominal muscles may be advantageously tensed both when exerciser 2 moves from an upright or substantially upright position, as shown, to a leaning position, i.e. a leaning forward or leaning back position, or from a leaning position to an upright or substantially upright position. When exerciser 2 sits on seat 186 such that abdomen 36 contacts back support 177 or a cushion attached thereto and feet 4 contact the floor surface, abdominal muscles are tensed by concentric contraction while back support 177 is angularly displaced rearwardly following application of a force by abdomen 36 or by chest 39 onto the back support. After the bodily applied force is released and back support 177 is angularly displaced forwardly, the abdominal muscles are tensed by eccentric contraction.

The resistance mechanism can be used to strengthen other muscles, in addition to the abdominal muscles. By standing in front of back support 177 and applying a force thereto by a hand or foot, for example in accordance with the Pilates exercise method, the exerciser can force the back support to be rearwardly displaced and to thereby strengthen the corresponding bodily portion that applied the force. Alternatively, a spring based device which is biased so as to return swingable plate 195 (Fig. 18) to its normal starting position after back support 177 has been rearwardly displaced may be employed in lieu of the resistance mechanism. The spring based device is connected to swingable plate 195 and to stationary plate 241 (Fig. 19A).

Elements added to the exercise apparatus can be used to strengthen other muscles, in addition to the abdominal muscles. For example, element 187, e.g. a bar, can be attached to the rear of head support 175, as shown in Fig. 16, so that mutually perpendicular rods 187 and 188 can be connected to element 187. Other exercises, such as in accordance with the Pilates exercise method, may be performed in conjunction with a training belt engaged with corresponding anchoring hooks 125 (Fig. 10), protrusions 261 (Fig. 21), recesses, or openings associated with leg support 173, e.g. opening 169 (Fig. 16).

Fig. 11 illustrates another embodiment of the invention wherein apparatus 130 is used for a plurality of users, e.g. 2000 users at a fitness center. Back support 7 is angularly displaceable by means of pneumatically extendable, vertically disposed cylinder 132. Vertical post 135 is attached to the end of leg support 3 which is distant from back support 7. To post 135 are attached a plurality of vertically spaced, horizontal leg rests 137 and a monitor 139 above leg rests 137. The exerciser can adjust the difficulty level of the exercise by placing his legs on one of the leg rests. Although the ending angle and difference between starting and ending angles of the circumferentially displaceable arm may be the same with respect to an exercise performed when the legs are placed on leg support 3 or when the legs are placed on one of the leg rests 137, the difficulty level increases as the legs are raised to a higher height. Two contact sensors 142 are positioned on each leg rest 137, one for each foot, and are in electrical communication with the controller of measurement unit 25. When a contact sensor 142 detects the pressure applied by a foot thereto, the controller determines the proportional increase in performance level attributed to the raised legs in accordance to predetermined rules. The performance or any other user- specific exercise related parameter can be viewed on monitor 139. The controller has sufficient memory to store the past performance and to determine the current performance level of any user interfacing with apparatus 130.

Fig. 20 illustrates an exercise apparatus 245 for strengthening core muscles when the legs of an exerciser are not stabilized. Apparatus 245 comprises a cable 246 downwardly extending from a portion of ceiling 247, to which the uppermost end of the cable is anchored. The middle of bar 248, or any other suitable leg rest, is connected to cable 246. Bar 248 may be fixedly attached to cable 246, to allow each foot 4 of exerciser 2 to be placed on a different portion of the bar. Bar 248 may also be releasably attached to cable 246, such as by a key, so that the height between bar 248 and mat 5 may be adjusted.

Since cable 246 is freely dangling, a reactive force is not applied to legs 8 of exerciser 2. Legs 8 therefore remain unstabilized, and the core muscles are forced to tense, in response to the placement of feet 4 on bar 248, in order to ensure body stability of exerciser 2 during the course of an exercise. When one of legs 8 is moved in a desired direction, such as forwardly, rearwardly, upwardly or downwardly, the orientation of cable 246 and bar 248 is accordingly changed, forcing other core muscles to be tensed. The level of difficulty can be adjusted by changing the height of bar 248 or by changing the angle of back support 249 relative to mat 5. Back support 249 may be one of the back supports illustrated in Figs. 1, 8 and 9 when the arm is locked in a retracted position, or one of the back supports illustrated in Figs. 12 and 15 when the back support is retained in a selected angular orientation.

Core muscles include those of the abdominals, such as the rectus abdominis, transverses abdominis, and internal and external obliques, those of the hip musculature, such as the iliopsoas, rectus femoris, sartorius, tensor fasciae latae, pectineus, gluteus maximus, medius and minimus, semitendinosus, semimembranosus, biceps femoris, adductor brevis, longus and magnus, gemellus superior and inferior, obturator internus and externus, quadratus femoris, and piriformis, and those of the spinal musculature, such as the erector spinae, quadratus lumborum, paraspinals, trapezius, psoas major, quadratus lumborum, multifidus, iliocastalis lumborum and thoracis, rotators, latissiums dorsi, and serratus anterior.

While prior art exercise methods, such as the pelvic thrust method whereby the exerciser lies on his back and his legs are bent 90 degrees at the hip, effectively strengthen the core muscles, the legs, or another bodily portion, remains unsupported for extended periods of time, causing the core muscles to be tensed for a similar period of time. Since the level of difficulty of prior art exercise methods for strengthening the core muscles is generally high, only experienced sport practitioners can perform certain exercises, particularly when a number of repetitions are recommended.

In contrast, the method of the present invention whereby a first bodily portion which is preferably a bodily extremity is supported in unstabilized fashion by bar 248, a second bodily portion is supported by mat 5, and preferably a third bodily portion is supported by back support 249, allows beginners and other inexperienced exercisers to exercise the core muscles for extended periods of time or by a selected number of repetitions.

Figs. 21-23 illustrate another embodiment of the invention for strengthening the core muscles when the legs of an exerciser are not stabilized. Exercise apparatus 250 comprises a freely rotatable ball element 255, from which extend leg rests. Abdominal exercises can be performed with the use of back support 251 and leg support 253, in conjunction with any of the embodiments described hereinabove, when the legs of an exerciser are stabilized. The exerciser may also perform exercises for strengthening the core muscles when his or her legs are placed on the unstabilized leg rests.

Bars 261 and 262, are connected to, and extend outwardly from diametrically opposite ends of, ball element 255, which is rotatably mounted within bearing element 267. The periphery of ball element 255 sufficiently protrudes from bearing element 267 so that ball element 255 and bars 261 and 26 connected thereto can freely rotate about three perpendicular axes, and associated with an angular displacement of at least 130 degrees in any given direction, and in some rotational directions, an angular displacement of up to 360 degrees. Stem 269 of bearing element 267 is fixedly attached within the interior of vertically displaceable bearing holder 268. Bearing holder 268 in turn is inserted in upwardly extending post 259. Post 259, which may be vertically or obliquely oriented, is connected to forward end 257 of leg support 253 by cross member 264. The relative vertical position of bearing holder 268 along post 259 can be set so that bearing holder 268 will be secured to post 259, for example by means of key 271when apertures 273 formed within post 259 will be aligned with apertures 275 formed in bearing holder 268.

Apparatus 250 facilitates the performance of additional exercises, particularly in accordance with the Pilates exercise method. Exercises may be performed, for example, in conjunction with a training belt engaged with a pair of protrusions 261. While four protrusions are illustrated in Fig. 21 on one side of the apparatus, three of which extending from the underside of leg support 253 and one of which extending from the rear face of back support 251, it will be appreciated that another four protrusions are provided on the other side of the apparatus.

Additional exercises for strengthening both the core muscles and other peripheral muscles may be performed with increased efficiency and requiring a reduced level of difficulty with respect to prior art methods by first placing a bodily portion on bars 261 and 262 and then performing the exercise. Exemplary additional exercises are selected from, and are not limited by, the group of curls, barbell curls, reverse curls, one-arm seated dumbbell triceps extensions, seated dumbbell presses, front dumbbell presses, alternate front arm raises, one-dumbbell front raises, bench presses, dumbbell flies, inclined dumbbell presses, dumbbell pullovers, right rows, dumbbell shrugs, sit-ups, and gym ladder sit-ups, as well known to those skilled in the art. Figs. 24-26 illustrate another embodiment of the invention wherein a repositionable stool unit can be used for both supporting a bodily portion in unstabilized fashion and for performing exercises according to the Pilates exercise method.

Stool unit 290 comprises a top planar surface 292, e.g. a horizontal surface, a vertical surface 294 extending downwardly from one end of horizontal surface 292, and a concave surface 296 laterally spaced from vertical surface 294 and adjoining the second end 297 of top surface 292. Stool unit 290 is made of metallic material to prevent movement thereof during the course of an exercise, or is otherwise easily anchorable to an underlying support surface, such as floor 299.

As shown in Fig. 24, stool unit 290 can be positioned such that vertical surface 294 is placed in front of forward end 257 of leg support 253. Post 259, which is releasably connected to vertical surface 294, is obliquely oriented so that an exerciser can place in unstabilized fashion his feet, or any other bodily portion, on bars 261 and 262, or any other suitable rests attached to freely rotatable ball element 255. An exerciser can therefore exercise the core muscles when another bodily portion is supported by back support 251 or by leg support 253.

As shown in Fig. 25, the curvature of concave surface 296 is substantially equal to that of forward end 257 of leg support 253. Accordingly, stool unit 290 can be positioned such that concave surface 296 is placed in abutting relation to leg rest forward end 257, so that top surface 292 will be continuous with top surface 256 of leg support 253. An exerciser 2 can therefore perform many different types of exercises with the apparatus, such as when torso 17 is placed on leg support top surface 256 and feet 4 are placed on stool top support 292.

In Fig. 26, stool unit 290 is anchored to leg support 253, e.g. by means of bolt 298 or any other suitable attachment means that is introducible through an opening formed in the leg support. An exerciser may therefore sit on top surface 292, for example, and perform one of many possible exercises according to the Pilates exercise method. While sitting on stool unit top surface 292, the exerciser can attempt to rearwardly displace back support 251 with his legs as a resistance mechanism, e.g. gas springs 180 and 181 of Fig. 18, resists such rearward displacement. The exerciser may also grasp grips 289 that are attached to corresponding sidewalls 301 of stool unit 290. This type of exercise is much more advantageous than prior art Pilates exercises whereby variable resistance to a displaceable element is provided by e.g. a spring based arm since the piston based resistance mechanism of the present invention provides a substantially constant resistance force throughout the entire stroke of the piston. The substantially constant resistance force prevents injury to the exerciser that is liable to result from an excessively quick-reaction spring based arm. Furthermore, entire muscles can be strengthened during the angular displacement of back support 251 by virtue of the substantially constant resistance force, and not just specific regions of a muscle that can be strengthened with use of prior art spring based devices.

To ensure a substantially constant resistance force, apparatus 310 illustrated in Fig. 27 may be employed. Apparatus 310 comprises a damper 315 for preventing immediate extension of the piston rods after being compressed. The two ends of damper 315, as well as the two ends of gas springs 180 and 181, are connected to lead screw nuts 226 and 228 (Figs. 18-19), respectively, causing a delay in the extension of the piston rods.

While some embodiments of the invention have been described by way of illustration, it will be apparent that the invention can be carried out with many modifications, variations and adaptations, and with the use of numerous equivalents or alternative solutions that are within the scope of persons skilled in the art, without departing from the spirit of the invention or exceeding the scope of the claims.

Claims

1. An abdominal muscle exercise apparatus, comprising: a. a leg support; b. an element that is angularly displaceable about a horizontal axis from a starting angle to an ending angle with respect to an underlying horizontal surface, said horizontal axis coinciding with an axle mounted in, or vertically spaced from, said leg support, wherein displacement of said element is initiated upon application of a bodily initiated force thereto during execution of an abdominal exercise; and c. means for determining an instantaneous angle of a selected portion of said element with respect to said horizontal surface, said instantaneous angle being indicative of an exerciser performance that is achieved during abdominal exercises.

2. The apparatus according to claim 1, wherein the element is a back support that is pivotally connected to the leg support.

3. The apparatus according to claim 1, wherein the element is a circumferentially displaceable arcuate arm which is biased to normally protrude from a back support and is retractable when a bodily portion applies a force thereto.

4. The apparatus according to any of claims 1 to 3, wherein the instantaneous angle determining means comprises a location detector for detecting an instantaneous location of an element characteristic region and means for correlating said instantaneous location to an instantaneous angle of the selected arm portion with respect to the horizontal surface.

5. The apparatus according to claim 4, wherein the correlating means is a measurement unit in which the location detector is housed.

6. The apparatus according to claim 4, wherein the location detector is an optical detector or a potentiometer.

7. The apparatus according to claim 5, wherein the measurement unit comprises a controller which receives a signal generated by the location detector, said signal being indicative of the instantaneous location of the characteristic region of the element.

8. The apparatus according to claim 7, wherein the controller is adapted to extract relevant parameters associated with the abdominal exercise from the received signal and to store the parameters in a log.

9. The apparatus according to claim 8, wherein exercise related parameters that are stored in the log are selected from the group of starting angle of exercise, ending angle, difference between starting and ending angles, duration of element displacement between the starting and ending angles, leg orientation, the number of exercises performed, the interval between exercises, and the number of sets of exercises performed.

10. The apparatus according to claim 9, wherein the measurement unit further comprises a selector in communication with the controller for inputting a user name, stored exercise related parameters being associated with a specified user.

11. The apparatus according to claim 8, wherein the measurement unit further comprises a display for viewing stored or selected exercise related parameters.

12. The apparatus according to claim 8, wherein the measurement unit further comprises a data interface in communication with the controller for viewing stored or selected exercise related parameters.

13. The apparatus according to claim 8, wherein the controller is operable in a controlled exercise mode during which exercise related parameters are controlled with respect to past performance or with respect to a user selected performance level, or in an uncontrolled exercise mode during which exercises are performed without comparison to controlled parameters.

14. The apparatus according to claim 13, wherein the measurement unit further comprises alerting means in communication with the controller for alerting a user exercising in a controlled exercise mode when one or more parameters of a currently performed exercise have a level inferior to that of the controlled parameters.

15. The apparatus according to claim 14, wherein the alerting means comprises an enunciator that emits an audible sound.

16. The apparatus according to claim 1, wherein the instantaneous angle determining means is a visual indicator.

17. The apparatus according to claim 2, wherein the back support is connected to one or more rails upwardly extending from a swingable plate, said swingable plate being pivotally connected to a first axle mounted to an underside portion of the leg support.

18. The apparatus according to claim 17, wherein the back support is height adjustable.

19. The apparatus according to claim 17, further comprising an enclosure for each rail and a slide element substantially parallel to the one or more rails which is slidingly engageable with a corresponding rail enclosure, said slide element being displaceable with respect to a corresponding rail following application of a force by the bodily portion of an exerciser onto the back support.

20. The apparatus according to claim 17, further comprising front and rear stops which are pivotally connected to second and third axles, respectively, mounted to corresponding underside portions of the leg support, said front and rear stops adapted to delimit the angular displacement of the swingable plate.

21. The apparatus according to claim 2, further comprising a mechanism for adjustably resisting a force applied to the back support.

22. The apparatus according to claim 3, wherein an arcuate, continuous guide way having substantially the same curvature as that of the arm is formed in both a measurement unit body and in an overlying back support body, the arm being insertable within the guide way and urged thereby to follow a circumferential path therealong, passing through a recess formed in the back support.

23. The apparatus according to claim 4, wherein the location detector comprises at least one elongated microswitch protruding from a surface of the arm and a plurality of flexible, electrically conductive levers protruding from the measurement unit body into a guide way interior, a microswitch being configured to cause a lever to pivot when being contacted thereby when the characteristic region of the element is in the vicinity of the corresponding lever.

24. The apparatus according to claim 3, further comprising means for retaining the back support at a desired angular orientation with respect to an underlying horizontal surface.

25. The apparatus according to claim 3, wherein the arm is upwardly biased by means of a spring or a torsion rod.

26. The apparatus according to claim 24, wherein the back support retaining means is a telescoping post.

27. The apparatus according to claim 1, further comprising means for maintaining legs in a raised position.

28. A core muscle strengthening exercise method, comprising the steps of supporting a first bodily portion in unstabilized fashion, supporting a second bodily portion in stabilized fashion, and performing a desired exercise, whereby core muscles are forced to tense in response to a selected orientation of said first bodily portion in order to ensure body stability of an exerciser during the course of said exercise.

29. The method according to claim 28, further comprising the step of supporting a third bodily portion in stabilized fashion.

30. The method according to claim 28 or 29, wherein the first bodily portion is a foot.

31. The method according to claim 28 or 29, wherein the first bodily portion is a hand.

32. The method according to claim 28 or 29, wherein the exercise that is performed is selected from the group of curls, barbell curls, reverse curls, one-arm seated dumbbell triceps extensions, seated dumbbell presses, front dumbbell presses, alternate front arm raises, one-dumbbell front raises, bench presses, dumbbell flies, inclined dumbbell presses, dumbbell pullovers, right rows, dumbbell shrugs, sit-ups, gym ladder sit-ups, retaining the first bodily portion in an outstretched position for an extended period of time, and an exercise in conjunction with a training belt.

33. System for strengthening core muscles, comprising means for supporting a first bodily portion in unstabilized fashion, and a first surface for supporting a second bodily portion in stabilized fashion, whereby core muscles are forced to tense in response to a selected orientation of said first bodily portion in order to ensure body stability of an exerciser during the course of an exercise.

34. The system according to claim 33, further comprising a second surface for supporting a third bodily portion in stabilized fashion, said second surface being angularly spaced from the first surface.

35. The system according to claim 33 or 34, wherein the means for supporting a first bodily portion in unstabilized fashion is height adjustable.

36. The system according to claim 33 or 34, wherein the means for supporting a first bodily portion in unstabilized fashion is a freely rotatable ball element to which is connected at least one element engageable by the first bodily portion.

37. The system according to claim 36, wherein the ball element is rotatably mounted within a bearing element which is attached to a bearing holder, said bearing holder being releasably securable to a post at a desired height.

38. The system according to claim 37, wherein the post is connected to a stool unit spaced from the first surface.

39. The system according to claim 33 or 34, wherein the means for supporting a first bodily portion in unstabilized fashion is a cable downwardly extending from a ceiling portion to which is connected at least one element engageable by the first bodily portion.

40. A method for selectively conditioning abdominal muscles, comprising the steps of providing an element that is angularly displaceable about a horizontal axis, selecting a starting angle and an ending angle of said element with respect to an underlying horizontal surface, and applying a bodily initiated force onto said element during execution of an abdominal exercise, whereby to angularly displace said element and to condition selected abdominal muscles or portions of abdominal muscles.

41. The method according to claim 40, further comprising the steps of providing a device for resisting the bodily portion initiated force applied to the element and adjusting a resisting force applied by the device.

42. The method according to claim 40, further comprising the step of determining an instantaneous angle of a selected portion of the element with respect to the horizontal surface, said instantaneous angle being indicative of an exerciser performance that is achieved during abdominal exercises.

43. A Pilates exercise method, comprising the steps of providing an element that is angularly displaceable about a horizontal axis, selecting a starting angle and an ending angle with respect to an underlying horizontal surface of said element, providing a device for resisting a bodily initiated force applied to said element, adjusting a resisting force applied by said device, and applying a bodily initiated force to said element, whereby to angularly displace said element and to strengthen selected muscles.

44. The method according to claim 43, wherein the magnitude of the resisting force is substantially constant.

45. The method according to claim 43, wherein the bodily initiated force is applied by a hand, foot or back.

46. The method according to claim 43, wherein the bodily initiated force is applied when an exerciser is in a sitting, standing or reclining position.